Thirteen crew members were rescued from a cargo ship that sank off southwestern Japan early on Wednesday during fierce winter winds but two have since died, the coast guard said.

Rescuers were searching for the remaining nine. The 6,651-tonne Hong Kong-registered “Jintian” issued a distress call late on Tuesday, the Japan Coast Guard said.

Media reported a person on the ship said it was listing and taking on water, and later reports said the 22 crew - all Chinese or Myanmar nationals - had transferred to lifeboats.

There was no immediate word on what caused the vessel, which was carrying lumber, to capsize. A Coast Guard spokesperson said winds were strong at the time.

The Coast Guard immediately sought assistance from patrol ships and aircraft in the vicinity west of Nagasaki, government spokesman Hirokazu Matsuno said. The ship sank at 2.46 a.m. (1746 GMT on Tuesday), he added, quoting other vessels in the area.

The Coast Guard “is also seeking cooperation from the Self-Defence Forces, South Korean Coast Guard, and vessels sailing near the waters," Matsuno told reporters. Western parts of Japan were battered by winter storms that brought freezing, windy conditions on Tuesday.

The area where the ship sank is between Nagasaki and South Korea's Jeju island, where hundreds of flights were cancelled on Tuesday because of harsh weather.

A ship ran aground in heavy wind off the southern Japanese islands of Okinawa on Tuesday. The 19 crew members were rescued, media reported.